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How the toughness in metallic glasses depends on topological and chemical heterogeneity

An, Qi and Samwer, Konrad and Demetriou, Marios D. and Floyd, Michael C. and Duggins, Danielle O. and Johnson, William L. and Goddard, William A., III (2016) How the toughness in metallic glasses depends on topological and chemical heterogeneity. Proceedings of the National Academy of Sciences of the United States of America, 113 (26). pp. 7053-7058. ISSN 0027-8424. PMCID PMC4932989. doi:10.1073/pnas.1607506113. https://resolver.caltech.edu/CaltechAUTHORS:20160615-153937054

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Abstract

To gain insight into the large toughness variability observed between metallic glasses (MGs), we examine the origin of fracture toughness through bending experiments and molecular dynamics (MD) simulations for two binary MGs: Pd_(82)Si_(18) and Cu_(46)Zr_(54). The bending experiments show that Pd_(82)Si_(18) is considerably tougher than Cu_(46)Zr_(54), and the higher toughness of Pd_(82)Si_(18) is attributed to an ability to deform plastically in the absence of crack nucleation through cavitation. The MD simulations study the initial stages of cavitation in both materials and extract the critical factors controlling cavitation. We find that for the tougher Pd_(82)Si_(18), cavitation is governed by chemical inhomogeneity in addition to topological structures. In contrast, no such chemical correlations are observed in the more brittle Cu_(46)Zr_(54), where topological low coordination number polyhedra are still observed around the critical cavity. As such, chemical inhomogeneity leads to more difficult cavitation initiation in Pd_(82)Si_(18) than in Cu_(46)Zr_(54), leading to a higher toughness. The absence of chemical separation during cavitation initiation in Cu_(46)Zr_(54) decreases the energy barrier for a cavitation event, leading to lower toughness.


Item Type:Article
Related URLs:
URLURL TypeDescription
http://dx.doi.org/10.1073/pnas.1607506113DOIArticle
http://www.pnas.org/content/113/26/7053/suppl/DCSupplementalPublisherSupporting Information
https://www.ncbi.nlm.nih.gov/pmc/articles/PMC4932989/PubMed CentralArticle
ORCID:
AuthorORCID
An, Qi0000-0003-4838-6232
Samwer, Konrad0000-0003-4266-449X
Goddard, William A., III0000-0003-0097-5716
Additional Information:© 2016 National Academy of Sciences. Contributed by William A. Goddard III, May 13, 2016 (sent for review March 8, 2016; reviewed by Takeshi Egami and Evan Ma). Published ahead of print June 15, 2016. This work was supported by Defense Advanced Research Projects Agency Grant W31P4Q-13-1-0010 (to program manager, John Paschkewitz), the Army Research Laboratory under Cooperative Agreement W911NF-12-2-0022 [Materials in Extreme Dynamic Environments (MEDE)], and National Science Foundation Grant Division of Materials Research (DMR)-1436985 (to program manager John Schlueter). Author contributions: Q.A., W.L.J., and W.A.G. designed research; Q.A., K.S., M.D.D., M.C.F., D.O.D., and W.A.G. performed research; Q.A. and W.L.J. analyzed data; and Q.A., K.S., M.D.D., M.C.F., D.O.D., W.L.J., and W.A.G. wrote the paper. Reviewers: T.E., University of Tennessee; and E.M., Johns Hopkins University. The authors declare no conflict of interest. This article contains supporting information online at www.pnas.org/lookup/suppl/doi:10.1073/pnas.1607506113/-/DCSupplemental.
Funders:
Funding AgencyGrant Number
Defense Advanced Research Projects Agency (DARPA)W31P4Q-13-1-0010
Army Research LaboratoryW911NF-12-2-0022
NSFDMR-1436985
Subject Keywords:cavitation; bulk metallic glass; molecular dynamics simulations; toughness
Issue or Number:26
PubMed Central ID:PMC4932989
DOI:10.1073/pnas.1607506113
Record Number:CaltechAUTHORS:20160615-153937054
Persistent URL:https://resolver.caltech.edu/CaltechAUTHORS:20160615-153937054
Official Citation:Qi An, Konrad Samwer, Marios D. Demetriou, Michael C. Floyd, Danielle O. Duggins, William L. Johnson, and William A. Goddard III How the toughness in metallic glasses depends on topological and chemical heterogeneity PNAS 2016 113 (26) 7053-7058; published ahead of print June 15, 2016, doi:10.1073/pnas.1607506113
Usage Policy:No commercial reproduction, distribution, display or performance rights in this work are provided.
ID Code:67947
Collection:CaltechAUTHORS
Deposited By: Tony Diaz
Deposited On:15 Jun 2016 23:25
Last Modified:26 Apr 2022 18:36

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